What steel type does GEC use for backsprings?

Ernie1980

Ernie1980

Gold Member
Joined
Apr 19, 2012
Messages
8,162
Greetings!

I have been searching for an answer to this question, but I have only seen a couple of passing remarks that simply say "stainless". However, I have a 71 where the spring has the same pepper spots that the O1 blade is covered with. On all of my custom traditionals the spring is the same steel as the blade, but the spring steel is never listed on production knives. (That I have seen at least)
Does it really matter?? No. Do the knives function? Yes. However, inquiring minds want to know!
 
It's definitely carbon steel, whether it's 1095 not sure. Here's my #55 from nearly a year of EDC rotation. This one has seen a lot of pocket time.

5DCAE3A7-9BDB-4D62-A248-EADCF8A52D12_zpstgeckopf.jpg
 
Blades and backsprings are made from the same steel and heat treated to the same Rc (Rockwell) hardness for most production and custom folders.
 
I have never had a knife with a spring the same hardness as the blade, I believe that it would be too brittle. Anyone have any contacts at one of the major traditional knife companies they could ask :)
 
Based on conversation with Bill Howard, GEC has their backsprings Rockwelled to within a point or two of the blades Rockwell. That is basically the accuracy of the Rockwell test on a batch of blades or springs. I don't think they test each individual piece. They do however hit each and every blade TWICE with a ball peen hammer to test it before finishing. I think the springs are also 1095 Carbon Steel.
 
Ernie1980 said:
I have never had a knife with a spring the same hardness as the blade, I believe that it would be too brittle. Anyone have any contacts at one of the major traditional knife companies they could ask :)
Click to expand...

Hardness and Brittleness are two entirely different things in steel.
 
From my experience, slipjoint backsprings are tempered to 48-49. Anything harder than that will result in broken springs. Ask me how I know :).
Nathan
 
rma100 said:
Based on conversation with Bill Howard, GEC has their backsprings Rockwelled to within a point or two of the blades Rockwell. That is basically the accuracy of the Rockwell test on a batch of blades or springs. I don't think they test each individual piece. They do however hit each and every blade TWICE with a ball peen hammer to test it before finishing. I think the springs are also 1095 Carbon Steel.
Click to expand...

:thumbup:

If the hardness of the blade is much higher than the spring, the spring will prematurely wear out. Likewise if they are two different materials due to friction.
 
Markesharp said:
:thumbup:

If the hardness of the blade is much higher than the spring, the spring will prematurely wear out. Likewise if they are two different materials due to friction.
Click to expand...

Yep, makes sense to me. They've got to be substantially similar in hardness or the blade will wear the spring badly over time.
 
That makes sense, yet in custom knives the spring is often advertised as having a hardness in the 40s while the blades are often in the 60s!
rma, thanks for the information about the springs!
 
Interesting discussion here, I have been enjoying it emensely! I was browsing the GEC site because I'm sure I have seen an image of blades and springs marked out into a single sheet of steel. I couldn't find the (possibly imagined) image but I did find this... Definitely carbon anyway ;)

ImageUploadedByTapatalk1401987835.192056.jpg
 
I encourage some of our resident custom smiths (Bose, Hampton, Erickson, Menefee, Dowell, et. al.) to chime in with their hardness numbers for springs. I was also under the impression that whenever I have seen hardness numbers listed, they were significantly softer than their blades were. Maybe Eric, ea42, has the info for Canal Street.
 
I just got off the phone with my friend Enrique Pena, I asked if he could explain this a little better for you folks. Hopefully he will chime in.

Kris
 
navin74 said:
From my experience, slipjoint backsprings are tempered to 48-49. Anything harder than that will result in broken springs. Ask me how I know :).
Nathan
Click to expand...

This...

If you had backsprings in the high 50's you would first off have a much harder time opening your knife and second if you did manage to get it open you can bet your spring would break pretty quickly. The spring has to be soft enough to bend yet hard enough to return to its original form over and over and over again.

If you felt so inclined you could test this by trying to bend a blade similarly to how a spring bends in a knife. The blade is most likely going to brake and if it somehow doesn't then I bet it is stuck in that bent shape and does not bounce back like the spring.
 
Vandal783 said:
This...

If you had backsprings in the high 50's you would first off have a much harder time opening your knife and second if you did manage to get it open you can bet your spring would break pretty quickly. The spring has to be soft enough to bend yet hard enough to return to its original form over and over and over again.

If you felt so inclined you could test this by trying to bend a blade similarly to how a spring bends in a knife. The blade is most likely going to brake and if it somehow doesn't then I bet it is stuck in that bent shape and does not bounce back like the spring.
Click to expand...

That makes sense and I think Case tempered the blade tang too.
 
With SS blades, they use 410, 420, or 420HC backsprings depending on the thickness. With 1095, they use 1095 backsprings. Both hardened to around 45-47.

They anneal the tang of the blade to about the same as the backspring.

They grab a handful (10 or so) from each batch (100+) that comes back from heat treat and hammer test them.
 
You must log in or register to reply here.
Back
Top